Utility of ICD Electrograms During Ventricular Tachycardia Ablation

With the increasing use of implantable cardioverter defibrillators (ICD) for primary prevention in patients with structural heart disease, an increasing number of patients are expected to develop their first episode of monomorphic ventricular tachycardia (VT) after an ICD is in place and the only documentation of the clinical arrhythmia will be the ICD electrogram (EG). The absence of a 12-lead ECG in patients with an ICD and sustained monomorphic VT represents a limitation when performing treatment with radiofrequency (RF) ablation. The analysis of ICD-EG during a RF ablation procedure is expected to provide a reference "model" of VT with clinical expression consisting of the electrical signal of the ICD during VT (which otherwise is not generally possible to obtain in ICD patients). This will allow for a more targeted approach to the substrate of the VT with clinical expression because: 1) if VT is induced by programmed stimulation, one can tell whether it is with clinical expression or not, and 2) if VT is not induced, ventricular pacing could be performed based on the comparative analysis of morphology and activation times of ICD-EG. These approaches will result in improved outcomes of the ablation procedure.

RF catheter ablation will be performed as usually done by each center. No ICD EGMs will be obtained and used during the ablation procedure (do not place the programming head over the ICD generator).

RF ablation procedure will be performed with the programming head over the ICD generator. ICD EGMs will be registered every time VT is induced and during ventricular pacing. ICD EGMs obtained during ablation procedure will be compared with the EGMs of the registered spontaneus VT and used to locate appropriate ablation sites.

Reduction in the proportion of patients free of recurrence in patients in whom 12-lead ECG of the spontaneous VT is not available and in those in whom hemodinamically tolerated VT is not induced

Improvement of spatial resolution of the ICD-EG after information from local ventricular endocardial acceleration is added

This outcome will be studied from the stored signal together with the ICD-EG on the device in the subgroup of patients with a device that allows to obtain this parameter. In the remaining patients, signals will be obtained noninvasively with a seismocardiogram using a highly sensitive accelerometer located in the sternal midline of the xiphoid process and simultaneously synchronized with the ECG.

Inclusion Criteria: Age 18 years or older Clinical indication for RF catheter ablation Presence of an implanted ICD At least 1 episode of spontaneous sustained monomorphic VT documented with ICD electrogram Presence of structural heart disease Able to obtain signed informed consent and willing to comply with study activity requirements Exclusion Criteria: It is anticipated that data can not be obtained during follow-up Unwilling or unable to provide informed consent Women who are or may potentially be pregnant Patients who are participating in another clinical trial

Yoshida K, Liu TY, Scott C, Hero A, Yokokawa M, Gupta S, Good E, Morady F, Bogun F. The value of defibrillator electrograms for recognition of clinical ventricular tachycardias and for pace mapping of post-infarction ventricular tachycardia. J Am Coll Cardiol. 2010 Sep 14;56(12):969-79. doi: 10.1016/j.jacc.2010.04.043.

Almendral J, Marchlinski F. Is it the same or a different ventricular tachycardia?: an additional use for defibrillator electrograms. J Am Coll Cardiol. 2010 Sep 14;56(12):980-2. doi: 10.1016/j.jacc.2010.03.081. No abstract available.

Almendral J, Atienza F, Everss E, Castilla L, Gonzalez-Torrecilla E, Ormaetxe J, Arenal A, Ortiz M, Sanroman-Junquera M, Mora-Jimenez I, Bellon JM, Rojo JL. Implantable defibrillator electrograms and origin of left ventricular impulses: an analysis of regionalization ability and visual spatial resolution. J Cardiovasc Electrophysiol. 2012 May;23(5):506-14. doi: 10.1111/j.1540-8167.2011.02233.x. Epub 2011 Dec 8.